1. Field of the Invention
The field of the invention is that of rotary impact clutches or impact wrenches, as identified hereinafter.
2. Description of the Prior Art
There are a substantial number of expired and unexpired patents directed to rotary impact clutches or wrenches. These tools are driven by a motor which typically may be an air motor. They operate typically to impart rotation onto a fastener and then to set the fastener by imparting blows or impacts to complete the tightening.
Typically the wrenches of this type in the prior art embody a combination which includes a rotatable hammer and dog means which may be carried by the hammer and which can move axially while rotating to deliver impacts or blows to an anvil. The anvil is an element usually carried on a camshaft which carries the socket or element to be rotated and impacted. Typically there is some type of cam means which may include a ball cam and which during rotation imparts the axial movement which moves the pins axially into position to impact on the anvil.
It has been known in the prior art to provide dog pins which may be carried either by the hammer for axial movement relative thereto or by the anvil. In typical prior art designs the dog pins may be carried in axial bores in the hammer member. The prior art, however, also teaches the carrying of the dog pins in axial slots or grooves that may be in the hammer or otherwise for the purpose of achieving results that are outlined in this type of prior art.
The deficiency in the prior art as described, has been that the construction with dog pins in axial bores is too complicated and cumbersome. With the dog pins in axial slots or grooves the pins would come out of the grooves rather than staying in them. This would cause the pins to hit the anvil on an edge breaking the pins. The herein invention overcomes the deficiencies of the prior art.
With respect to the prior art, U.S. Pat. No. 2,285,638 is considered typical of that type of combination wherein dog pins are carried in bores. With respect to the prior art of which the herein inventor has knowledge, it is considered that the following patents are relatively the most relevant: U.S. Pat. Nos. 3,001,428; 3,174,597; 3,414,065; and 3,428,137.